CODEWITHSUNDEEP
javaregex
user2060677
user2060677

Reputation: 35

Regex for a custom 'HTTP GET style' request

I'm trying to parse (Java) a custom GET style request, and I'd like to do that through a regular expression.
The request is formatted like: 

GET myCommand?parameter1=value&parameter2=value&parameter3=value&parameter4=value

The number of params is variable, but at least one param is required.

Can someone help me with this regex?

Upvotes: 1

Views: 3532

Answers (3)

Shailesh
Shailesh

Reputation: 388

Following is regex that will work with any request URL with query parameters: .+?(\?((\w+?=.+?)&)*\w+?=.+)?$

Here .+? is matching string before query parameters. Let break regex: (\?((\w+?=.+?)&)*\w+?=.+)?

((\w+?=.+?)&)* represents zero or more key-value pairs joined with &
\w+?=.+ represents last key-value pair

Hope this helps. Let me know if you need more help.

Upvotes: 0

Bohemian
Bohemian

Reputation: 425208

Here's how to parse it all into java variables using 4 lines:

String command = input.replaceAll("(^\\w+ )|(\\?.*)", "");
Map<String, String> params = new LinkedHashMap<String, String>();
for (String pair : input.replaceFirst(".*?\\?", "").split("&"))
    params.put(pair.split("=")[0], pair.split("=")[1]);

Note that using a LinkedHashMap iterates in input order.

Here's a little test using your input (modified a little to have distinct values):

public static void main(String[] args) throws Exception {
    String input = "GET myCommand?parameter1=value1&parameter2=value2&parameter3=value2&parameter4=value4";
    String command = input.replaceAll("(^\\w+ )|(\\?.*)", "");
    Map<String, String> params = new LinkedHashMap<String, String>();
    for (String pair : input.replaceFirst(".*?\\?", "").split("&"))
        params.put(pair.split("=")[0], pair.split("=")[1]);
    System.out.println("Command=" + command);
    System.out.println("Params=" + params);
}

Output:

Command=myCommand
Params={parameter1=value1, parameter2=value2, parameter3=value2, parameter4=value4}

Upvotes: 3

jpm
jpm

Reputation: 3155

GET myCommand\?([a-z0-9]+)=(.+)(&([a-z0-9]+)=(.+))*

Now just replace [a-z0-9]+ with a regex for valid identifiers, .+ with a regex for valid values, and escape as required by your language of choice, and you should be good to go.

Upvotes: 0

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